public class e4 {
        public static void main(String[] args) {
            String s = "itcast";
            System.out.println("将it替换成cn.it的结果:" + s.replace("it","cn.it"));
            String s1 = "   i t c a s t   ";
            System.out.println("去除字符串两端空格后的结果:" + s1.trim());
            System.out.println("去除字符串中所有空格后的结果:" + s1.replace(" ",""));
        }
}
